IO Fencing

SCSI_3 Persistant —–> accepting I/O ‘s from multiple nodes/hosts
SCSI-3 PR enables access for multiple nodes to a device and simultaneously blocks access for other nodes.
SCSI-3 PR uses a concept of registration and reservation. Each system registers its own “key” with a SCSI-3 device

I/O Fencing Service/Driver:
I/O fencing uses GAB port b for communication.Fencing is started with the vxfenconfig -c command.
The fencing driver vxfen is started during system start up using /etc/rc2.d/s97vxfen.

6.Test the diskgroup for I/O fencing compatibility.Option “-r” will run the test in non-destructive mode.
Arena-Node2#/opt/VRTSvcs/vxfen/bin/vxfentsthdw -r -g fendg

VERITAS vxfentsthdw version 5.1 Solaris

The utility vxfentsthdw works on the two nodes of the cluster.
The utility verifies that the shared storage one intends to use is
configured to support I/O fencing. It issues a series of vxfenadm
commands to setup SCSI-3 registrations on the disk, verifies the
registrations on the disk, and removes the registrations from the disk.

The logfile generated for vxfentsthdw is /var/VRTSvcs/log/vxfen/vxfentsthdw.log.11074

Enter the first node of the cluster: node1
Enter the second node of the cluster:node2

Unregistration test for disk failed on node node2.
Unregistration from one node is causing unregistration of keys from the other node.
Disk is not SCSI-3 compliant on node node2.
Execute the utility vxfentsthdw again and if failure persists contact
the vendor for support in enabling SCSI-3 persistent reservations
Removing test keys and temporary files, if any…
The above test should be password in a order to use the diskgroup as coordinator DG.
Note:As the above results,my test is failed due to SCSI-3 PR issue.

7.Start the fencing driver using script on all cluster nodes.
# /sbin/vxfen-startup
Node:/etc/vxfentab will be updated whenever fencing driver re-initializes.

8.Close the cluster configuration on all the cluster nodes.
# haconf -dump -makero

For your information,we can configure I/O fencing using CLI option as well,
./installvcs -fencing
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vxfenadm utility
Administrators can use the vxfenadm command to troubleshoot and test fencing configurations. The command’s options for use by administrators are: